Abrading machine



Match 27, 1934.

D. c. PAGE ABRADING MACHINE Filed July l9, 1952 4 Sheets-Sheet l uw m 0.231? March 27, 1934. 0., CJPAGE ABRADING MACHINE.

Filed July 15, 1932 4 Sheets-Sheet 2 nm m (3. 33;: a, a, my

March 27, 1934.

D. C. PAGE ABRADING MACHINE Filed July 19, 1932 4 Sheets-Shet xmw ,gmnntot March 27, 1934. c, PAGE 1,952,458

ABRADING MACHINE Filed July 19, 1932 4 Sheets-Sheet 4 gwuentov Dm m 0.PM

Patented Mar. 27, 1934 UNITED STATES PATENT OFFICE ABRADING MACHINEDwight C. Page, Worcester, Mass, assignor to The Heald Machine Company,Worcester, Mass., a corporation of Massachusetts Application July 19,1932, Serial No. 623,402

25 Claims. (01. 51-50) the workpiece, to mount the workpiece in sep-'arate machines, the first of which procures a grinding operation on theworkpiece to reduce the workpiece substantially to the desired size andthe second of which operates to polish the ground surface in order toform a suitable finished surface on the workpiece. ble, particularly inmachines in which the workpiece is clamped in a chuck, to mount theworkpiece for rotation in the second machine so that it will rotateabout the same axis of rotation about which it was rotated in the firstmachine and accordingly the polishing operation by the second machinedoes not result in a uniform polishing over the entire ground surface ofthe workpiece. Furthermore, the necessity for removal of the workpiecefrom one machine and for mounting it in the second machine to completethe abrading operation results in an appreciable loss of time. It isaccordingly the principal object of the present invention to provide forsuccessive abrading operations such V as a grinding operation andthereafter a polishing operation on the same surface of a workpiece andin a single machine by separate abrading members carried on the samerotating spindle.

According to the present invention, which is, in certain respects, animprovement on the copending application of Taylor, Quimby and Lippard,Serial No. 623,400, filed .July 19, 1932, now Patent No. 1,949,552,dated March 6, 1934; a plurality of abrading members are mounted inaxially spaced relation on a rotating spindle. One of the members ispositioned in operative relation to the surface of the workpiece to beoperated upon and is maintained in that position during the preliminarygrinding operation. The workpiece and the abrading members "are then 0shifted axially relative to one another to bring It is practicallyimpossi wheels and the workpiece, and for dressing the wheels tomaintain suitable cutting surfaces.

One of the features of the invention resides in a novel mechanism forlocating the separate abrading members successively in operativerelation to the workpiece, this mechanism being a different form ofmechanism from that shown in the above noted copending application. Inaccordance with this feature of the invention, the position of thecarriage, which determines the position of the abrading members relativeto the workpiece, is determined by stop members mounted on saidcarriage, and the stop members are shifted longitudinally of saidcarriage when it is desired to change the position of the abradingwheels relative to the workpiece as in positioning one of the wheels inengagement with the work and removing the other from operativeengagement. The mechanism for shifting said stops on the table ispreferably actuated by fluid under pressure.

An additional feature of the invention resides in mechanism by which arough grinding operation and subsequently a slower finish grindingoperation may be procured with one of said abrading members and apolishing operation thereafter procured with the other of said abradingmembers. Other and further objects and advantages of the invention willappear from the following detailed description taken in connection withthe accompanying drawings in which:-

Fig. 1 is a front elevation of an abrading machine embodying theinvention.

Fig. 2 is a diagrammatic view of the workpiece and abrading wheels inthe position for the preliminary abrading operation.

Fig. 3 is a fragmentary elevation of the mecha-" nism by which themachine carriage is positioned and reciprocated, said mechanism being inthe position for the preliminary abrading operation shown in Fig. 2.

Fig. 4 is a diagrammatic view corresponding to Fig. 2 with the workpieceand abrading wheels in a position for the final abrading or polishingoperation.

Fig. 5 is a view similar to Fig. 3 with the parts in the position forthe final abrading or polishing operation, shown in Fig. 4.

Fig. 6 is a vertical section along the line 6-6 of Fig. 5 looking in thedirection of the arrows.

Fig. 7 is a sectional view through the crossfeed mechanism showing thestructure by which the abrading wheels are withdrawn radially from theworkpiece.

ersing movement between the abrading members and the workpiece. In theconstruction shown, the table 1 supports and carries a wheelhead 3 whilethe workpiece a which is to be operated upon is mounted in suitablesupporting means on the workhead 4, the latter being carried by a bridge5 which spans the slideways provided by the base for the longitudinalback and forth movement of the table 1. An abrading wheel spindle 6,which is suitably journaled in the wheelhead 3, is rotated in anysuitable manner as by an electric motor 7 mounted on the table, andcarries a plurality of abrading wheels 9 and 10 by which successiveabrading operations on the same workpiece are procured. The workpiece ais mounted in a suitable work supporting member 8 carried by a spindlejoumaled in the workhead 4, said spindle being rotated desirably at aslower speed than the spindle 6 in any suitable manner, not shown.

The reciprocations of the table 1 to cause the rotating abrading membersto make the required internal traverse of the rotating workpiece may beimparted in any well-known manner as by the use of the fluid pressurecontrolling and nevering mechanism describedin United States LettersPatent No. 1,582,468, granted April 27, 1926 to Heald and Guild. Suchmechanism is wellknown; it is sufficient to note, for purposes of thepresent application, that the driving means employed, be it hydraulicdrive or any other type, procures the reversal of the table at each endof the normal working stroke by the use of spaced adjustable dogs 11 and12 carried by the table 1 and adapted alternately to engage and move areversing lever 13 which latter, during the abrading operation, wheneither of the wheels is moving back and forth within the workpiece issituated between said reversing dogs in a position to be struckalternately by said dogs and by the resultant movement first in onedirection and then in the other to effect a reciprocation of the table1.

The crossfeed movement between the workpiece and the abrading wheels tofeed said wheels laterally against the surface being ground is procuredin this machine by lateral movement of the wheelhead 3 on the table 1 inany suitable manner as by the mechanism disclosed in Patent No.1,682,673, granted August 28, 1928 to Taylor. It

is sufiicient to note that the wheelhead 3 is mounted on a cross-slide14, Figs. 7 and 8, which is adapted to have a transverse movement on thereciprocatory table 1, and movement of the crossslide is procured byrotation of a crossfeed screw 15, the latter being suitably connected tothe cross-slide 14. Rotation of the crossfeed screw is effected by a cam16, Fig. l, adjustably mounted on a bracket 17 extending from the bridge5. Said cam, during the reciprocation of the table 1, engages a roller18 carried on a pivotally mounted arm 20 for rocking of said arm,'andthe latter carries on the outer end thereof a pawl 21 which during therocking of the arm 20 engages with a ratchet wheel 22 positivelyconnected to the crossfeed screw for rotation of said screwsiCrossfeedmovement of the abrading wheels is thus responsive to the reciprocatorymovements of the table 1.

The abrading wheel spindle carries, as above stated, a pair of abradingwheels 9 and 10, the former constituting a wheel for grinding of theworkpiece a substantially to the desired size, and the wheel 10constituting a wheel suitable for polishing the workpiece to provide asuitable finished surface on said workpiece. In the operation of themachine, the abrading wheel 9 is first reciprocated longitudinally overthe surface of the workpiece, as shown in Fig. 2 and, after theworkpiece is ground substantially to the desired size, the workpiece aand abrading wheels are axially shifted relative to one another for thepolishing operation during which the polishing wheel 10 is reciprocatedover the surface of the workpiece, as shown in Fig. 4.

At the beginning of the grinding operation, the carriage 1 is movedlongitudinally of the machine by the carriage actuating means to bringthe grinding wheel 9 into operative engagement with the workpiece andthe arrangement is such that the grinding wheel 9 is given alongitudinal traversing movement over the surface of the workpiecewithout causing the wheel 10 to engage said surface. The longitudinaltraversing movement of said wheel 9 procures a transverse crossfeedmovement of the grinding wheel against the surface of the work, as abovepointed out, to procure a cutting action on said workpiece.

The reciprocation of the wheel 9 for the Tinding operation is controlledby the spaced dogs 11 and 12 which, as above stated, are carried on adog bar 23 on the front of the table 1 and the grinding operation of thewheel 9 on the workpiece is under the control of these dogs until theworkpiece has been ground to a predetermined size which is smaller thanthe finished size, at which time, in response to entry of a roughing orpreliminary gauge within the bore of the workpiece, an extended movementof the carriage is effected in order to procure a dressing operation onthe wheels 9 and 10, the wheel 9 being thereafter returned to theoriginal grinding position.

The extended movement of the carriage is procured in any suitable manneras by mechanism of the type fully disclosed in United States LettersPatent No. 1,682,672, issued August 28, 1928 to Guild, said mechanismbeing under the control of a gauge of the type disclosed in UnitedStates Letters Patent No. 1,532,302, issued April 21, 1925 to Conradsonor in United States Letters Patent to Kempton and Gallimore No.1,713,719, issued August 15, 1929. In either of the latter patents,entry of the gauge within the bore of the workpiece closes a circuit bywhich an extended movement of the carriage is procured.

For the purposes oi the present invention, it is sufiicient to note thatclosing of the circuit by entry of the roughing gauge within the bore ofthe workpiece procures sliding movement of the left hand reversing dog11 to the left, thereby permitting the carriage to move to the rightbeyond the normal reciprocatory position.

Referring first to Fig. 9, which shows the wiring diagram, electriccurrent is supplied by a generator 24, one terminal of which is.connected by a lead 25 to a ground 26 and the other terminal of which isconnected by a supply lead 27 to the movable element 28 of a switch 29,the latter being positioned, as shown in Fig. 1, on the front of themachine. The stationary plate or contact 30 of the switch 29 isconnected by a lead 31 'to one terminal of the electromagnet 32, theother terminal of said electromagnet being connected by a lead 33 to agauge contact 34, and the cooperating gauge contact 35 is connected by alead 36. to a ground 37. Entry of the above noted roughing gauge withinthe bore of the workpiece which, as above stated, occurs before theworkpiece reaches finished size, provides an electrical connectionbetween the gauge contacts 34 and 35, thereby energizing theelectromagnet 32 to procure attraction of an armature member 38 of saidelec tromagnet. Attraction of the armature procures elevation of a leverarm 40, which is pivoted on the base of the machine 1 and integral withthe armature 38.

Elevation of said lever raises the upper end of said lever into aposition to procure longitudinal shifting movement of the dog '11 alongthe table for the extended movement of the carriage. As shown in Figs.1, 3 and 5, the left hand table dog 11 which normally limits the righthand movement of the table 1 is carried by a block 41 which is mountedso as to be ca-e pable of sliding freely longitudinally of the dog bar23. Said block 41, during the normal working reciprocations of thegrinding wheel 9, is held in definite spaced relation to a block 42 onthe dog bar 23 by a latch lever 43 pivoted on the block 42 with the freeright hand end of said lever engaging a notch, not shown, in the block41. When the lever arm is elevated, the free end of the latch 43 isliftedfrom the notch by the free end of said lever arm, and the dog 11then moves to the left without actuating the reversing member 13 untilthe block 41 carrying said dog 11 comes into engagement with the block42 at which time the backing afforded by the block 42 causes the dog 11to shift the reversing member 13, the movement of the table is reversedand the grinding wheel 9 is returned to operative position.

During the extended movement of the carriage, a double wheel dressingdevice 44, Fig. 1, mounted on the base of the machine and carryingspaced adjustable dressing tools 45, the spacing of which corresponds tothe spacing of the wheels 9 and 10 on the wheel spindle, is rockeddownwardly to position said dressing tools in the path of the Wheels byany suitable mechanism such as that shown in United States LettersPatent No. 1,779,094, granted October 21, 1930, to Heald and Guild. Itis sufiicient to note for the purposes of' the present application thata depending lever arm 46, Pg. 9, integral with the armature 38 isconnected to a valve member 47, Fig. 10, and. in response toenergization of the electromagnet 32, procures shifting movement of saidvalve member 4'7 to the right away from the normal position shown inFig. 10.

Referring to Fig. 10, fluid pressure is supplied oy a pump 48 through aconduit 50 to an inlet port 51 in the valve casing 52 for the valve 47,the latter normally closing the port 51. An outlet port 53 in the casing52 is connected by a pipe .54 to a cylinder 55 in which is mounted apiston 56 suitably connected to the dressing device 44. The casing 52 isalso provided with an exhaust port 5'7. When the valve 47 is shifted tothe right in response to entry of the roughing gauge within the bore ofthe workpiece, as above pointed out, fluid under pressure enters thecylinder 55 to rock the dressing tools into operative position.

The circuit through the. electromagnet 32 is broken during the extendedmovement of the carriage to avoid a repetition of the dressing operationby an arm 58 on the block 42, said arm hanging in a position to engage aportion of the switch 29 to rock said switch for moving the contact 28out of engagement with the stationary contact 30. Breaking of thecircuit through electromagnet 32 releases the armature 38, so that saidarmature returns to the position of Fig. 9, returning the lever arm 40to-inoperative position. The shifting of the arm 46 at the same timereturns the valve 47 to the position shown in Fig. 10, permitting fluidto exhaust from the cylinder 55, the dressing tools then being returnedto the inoperative position of Fig. 1 by any suitable mechanism. Thewheels 9 and 10 are thus dressed simultaneously and thus smooth sharpcutting surfaces are provided for each successive abrading operation.

Upon reversal of the carriage at the end of the extended movement andreturn of the grinding wheel 9 into operative engagement with theworkpiece, the dog 11 is restored to normal position in any suitablemanner as by the mechanism disclosed in the above cited Guild Patent No.

, shown, of the type shown in the above cited Conradson or Kempton andGallimore patentsenters the bore of the workpiece to procure axialshifting of the abrading wheels relative to the workpiece to withdrawthe wheel 9 from the'workpiece and to position the polishing wheel 10 inoperative engagement with the same surface of the workpiece. Referringto Fig. 9, entry of the above noted finish gauge within the bore of theworkpiece provides an electrical connection between the gauge contacts60 and 61. Contact 60 is connected by a lead 62 to a ground 63, and thecontact 61 is connected by leads 64 and 65 to one terminal of anelectromagnet 66, the other terminal of which is connected by a lead 6'7to the lead 2'7, the latter being connected to one terminal of thegenerator 24. Connection of the contacts 60 and 61 thus energizes theelectromagnet 66 causing attraction of the armature member 68 andthereby procuring counterclockwise rotation of a depending arm '70integral with said armature, the latter being pivotally mounted on 7 thefront of the machine as shown in Fig. 1.

The lower end of said arm '70 is connected to a valve '71, Fig. 10, bywhich the position of the reversing dogs 11 and 12 is varied. Referringto Fig. 10, the valve casing '72 for the valve '71 has an inlet port '73connected by apipe '74 to the supply pipe50 from the pump 48 and is alsoprovided with spaced exhaust ports '75 and '76. Spaced outlet ports '77and '78 in the casing '72 are connected by conduits 80 and 81(represented by pipes 80 and 81 in Fig. 10) to the left and hight handends respectively of a cylinder 82, the latter being mounted on thefront of the table 1 adjacent the right hand end thereof, as best shownin Fig. 1. With the valve '71 in the normal position shown, fluid underpressure is supplied movement of the dog. bar 23 and similarly the' tothe right hand end of the cylinder 82 to support a piston 83 mountedtherein adjacent the left hand end of' said cylinder. Upon shiftingmovement of the valve 71 to the right, however, in response toenergization of the electromagnet 66, fluid under pressure is admittedto the left hand end of the cylinder 82, thereby urging the piston 83and the piston rod 84 connected thereto to the right.

This movement of the piston rod 84 to the right operates to shift theposition of the reversing dogs 11 and 12. Referring to Figs. 3, 5 and 6,the table 1 has secured thereto, on the front edge thereof, a bracket 85which receives a dovetailed slide 86 formed on the dog bar 23 to providefor sliding movement of the latter longitudinally of the table.Longitudinal movement of the dog bar 23 on the table 1 will shift theposition of're-' ciprocation of the carriage by shifting the position ofthe dogs 11 and 12. To this end, the piston rod 84 has an elongatedthreaded portion 87 which engages within a socket provided by a bracket88 secured to the bar 23, and a clamping nut 90 prevents rotation ofsaid threaded portion 87 to maintain the spacing of the bracket 88 onthe bar 23 from the piston 83 on the opposite end of the piston rod.

Longitudinal shifting movement of the bracket 86 in response to thefluid pressure entering opposite ends of the cylinder 82 is limited byspaced pairs of check nuts 91 and 92 on the threaded portion 87 of thepiston rod, the latter being slidable in an opening in a bracket 93secured to the table 1-. The nuts 91 engage the left hand side of thebracket 93 to limit the right hand nuts92 limit the left hand movementof the dog bar 23, the extent of movement being readily varied byshifting either pair of nuts 91 or 92 on the threaded portion 87. Thus,as the electro magnet 66 is energized, fluid under pressure is admittedto the left hand end of the cylinder 82 to procure movement to the rightof the piston 83 and corresponding movement to the right of the dogs 11and 12. This longitudinal shifting of the dogs 11 and 12 procures axialshifting of the abrading wheels .to withdraw the wheel 9 from theworkpiece and position the wheel 10 in engagement with the same surfaceof the workpiece, as shown in Fig. 4. The wheel 10 is'accordinglyreciprocated over the surface of the- 'table, is discontinued at anytime during the abrading operation being preferably discontinued justprior to or at the time that the finish gauge, which operates to bringthe polishing wheel 10 into engagement with the workpiece, enters thebore of said workpiece. To this end, the ratchet wheel 22 has securedthereto a cam 94 which, in response to the clockwise rotation of theratchet 22 during the crossfeed movement, is carried beneath the pawl21, thereby preventing further actuation of the ratchet wheel inresponse to the movements of the pawl. Said cam is positioned forangular adjustment on said bracket wheel in; any suitable manner toengage beneath'said pawl prior to or at the time that the finish gaugeenters the workpiece. A

The axial shifting of the abrading wheels to position the polishingwheel 10 in engagement the left away from the bore of the workpiece, at

the time the polishing wheel 10 is placed in operative position, lay-amechanism of the type fully disclosed in United States Letters PatentNo. 1,830,358, issued November-3, 1931 to Guild and Burns. Referring toFig. 10, a pipe 95 connects the inlet port of a cylinder 96 to the pipe80 which latter is normally connected to the exhaust so that a piston 97in the cylinder 96 is normally at the right hand end of said cylinder.Movement of the piston 97 tosthe left withdraws the gauges axially tothe left away from the workpiece through mechanism disclosed in theabove cited Guild and Burns Patent No. 1,830,358. This movement of thepiston 9'7 is procured in response to shifting movement of the valve 78to the right which movement, as above stated, establishes fluidconnection from the pump 48 to the pipe or connection 80 and accordinglyadmits fluid under pressure to the right hand end of the cylinder 96procuring a withdrawal of the gauges from the workpiece. Since the valve'78 remains in its right hand position during the remainder of theabrading operation while the polishing wheel is in operative position,the gauges are held in their spaced inoperative relation during the timethat the grinding wheel 9, is in a position to contact with said gauges.

In order to provide a suitable polishing pressure between the polishingwheel and the workpiece, said wheel may be somewhat larger in diameterthan the grinding wheel so that, as the polishing wheel is shifted intooperative position, the relative position of the cross-slide beingunchanged, said polishing wheel engages the surface of the workpiecewith a relatively greater pressure than the pressure exerted by thegrinding wheel. In order that the polishing wheel may be' somewhatlarger than the grinding wheel, the spaced adjustable dressing tools 45,above noted, are arranged so that the vertical plane defined by thepoint of the dressing tool for the polishing wheel when said tool is inop- 1 erative position is spaced a greater distancefrom the axis ofrotation of the workpiece than the vertical plane defined by thedressing tool for the rough grinding or abrading wheeL. By thisadjustment of the dressing tools, the polishing wheel will be maintainedat all, times at a predetermined greater diameter than the grindingwheelso that at each successive abradingoperation, the relative positions ofthe cutting surfaces of the abrading wheels is the same.

After the polishing wheel has been shifted into operative engagementwith the workpiece, the table 1 is reciprocated to procure a traversingmovement of said polishing wheel over the surface of the workpiece, thepolishing operation being under the control of a time relay mechanismwhich is set in operation when .electrical connection between the gaugecontacts 60 and 61 is established to procure axial withdrawal movementof the abrading wheels from the workpiece a predetermined timethereafter. Referring to Fig. 9, the supply lead 27 from the generator24 is connected by a lead 98 to one terminal of a solenoid 100 and theother terminal of said solenoid is connected by a lead 101 to the lead64 from the gauge contact 61. Electrical connection of the gaugecontacts 60 and 61 thus energizes the solenoid 100, thereby causingattraction of a switch member 102 to establish electrical connectionbetween stationary contacts 103 and 104. Contact 104 is connected to aground 105 by a lead 106 and the contact 103 is connected by a lead 107to one terminal of a time relay motor 108. The other terminal of saidmotor is connected by a lead 109 to one blade 110 of a double bladeswitch 111 and, in the normal position of said switch, the blade 110 isin engagement with a contact 112 which is connected to the lead 27 fromthe generator 23 by a lead 113. Elevation of the switch member 102 bythe solenoid 100. thus establishes a circuit by which the motor 108 isset in operation.

The motor 108 comprises a time relay motor which operates apredetermined time after it is set in operation to rock the switchmember 111 and bring a second blade 114 thereof into engagement with acontact 115, the latter being connected by a lead 116 to a ground 117.The

blade 114 is normally connected through a lead 118 to one terminal of anelectromagnet 120, the other terminal of which is connected to the lead27 by a lead 121. Accordingly, a predetermined time after the gaugecontacts 60 and 61 are connected, the electromagnet 120 is energized tocause attraction of an armature member 122 and consequent elevation of alever arm 123 integral with the armature, said lever arm being pivotedon the front of the machine on the same stud 124 which provides thepivotal support for the lever arm 40.

Elevation of the lever arm 123 raises the upper end thereof intohorizontal alinement with the left hand reversing dog 11 which, as shownin Figs. 2 and 4, is pivotally mounted on the block 41. With the leverarm 123 in raised position,

the dog 11 is elevated thereby during movement of the carriage to theright and passes over the reversing lever 13 without rocking said leverso that the carriage continuesbeyond its. normal reciprocating positionto the rest position shown in Fig. 1 where it is brought to rest in themanner disclosed in the above cited patent to Heald, et al. No.1,582,468.

When the run-out of the carriage to rest position is initiated by theelevation of the lever arm 123, the polishing wheel is withdrawnradially from contact with the workpiece to avoid scratch lines on thepolished surface. The back-off mechanism for the radial withdrawalmovement is similar to that disclosed in United States Letters PatentNo. 1,816,082,-issued July 28, 1931 to Heald and Guild. This mechanismis not of itself the invention in the present case; it is suflicient tonote that as the lever arm 123 is elevated, a depending lever arm 125integral therewith procures shifting movement of a valve 126 to whichsaid depending arm is connected for actuating the mechanism by which thewheel is radially withdrawn from the workpiece. Referring to Fig. 10,the valve casing 127 for the valve 126 has an inlet port 128 connectedby a pipe 130 to the supply pipe 50. The casing also has an outlet port131 connected by a pipe 132 to a cylinder 133 on the back of themachine, as shown in Figs. 7 and 8, and an exhaust port 134. The valve126, which is normally in the position shown in Fig. 10, closes theinletport 128 to prevent entry of fluid under pressure into the cylinder 133.Upon shifting movement of. the valve 126, however, in response tomovement of the arm 125, fluid connection is provided between the port128 and the outlet port 131, and fluid under pressure is admitted to thecylinder 133.

I Referring now to Figs. 7 and 8, the crossfeed shaft 15 adjacent therearward end thereof carries a pair of spaced ball bearing members 135which are supported against movement on said shaft. The outer races ofsaid ball bearing members support a sleeve 136 for rotation about thecrossfeed shaft and prevent axial movement of the sleeve 136 on saidshaft, and the outer surface of said sleeve is threaded'to engage in athreaded portion 137 of the table 1. So long as the member 136 issupported against rotation, the shaft 15 is held against axial movement;rotation of said member 136, however, will procure axial shifting of thecrossfeed shaft 15 which will accordingly shift the cross-slide 14 andwithdraw the polishing wheel radially from the work. To procure rotationof the sleeve 136, a substantially annular member 138 is secured theretoand is provided with an am 140; the latter carries a roller 141 which,during the normal reciprocations of the carriage, moves back and forthin a horizontal path directly above a horizontal bar 142. Said bar 142is pivotally connected to a pair of links 143 and 144 which arepivotally mounted on the machine frame on studs 145 and 146, the spacingof said studs corresponding to the spacing of the pivotal connections ofthe links with the bar 142. The link 144 has an arm 147 provided with aroller. 148 which is located above and engages with the upper surface ofa piston 150 slidable in the cylinder 133. Move-,

tion of the link 141 and accordingly the vertical movement of the bar142.

The sleeve 136 is normally maintained in the position shown in Figs. 7and 8 by a spring 153, one end of which engages a pin 154 on thecarriage 1 andthe other end of which engages a pin 155 on a cap 156secured to the rearward end of the annular member 138. Thecounterclockwise rotation of the cap 156 in response to the pull of thespring 153 is limited by a projecting portion 157 on the member 136,said projecting portio engaging a surface 158 on the table 1.

' During the run-out of the carriage to rest position, the shifting dogbar 23 is restored to the original position. Referring to Figs. 1 and 3,the bracket 88 has secured thereto a horizontal extending bar 160 whichis in alinement with and in a position to rock a lever arm 161counterclockwise as the carriage moves to the right. The arm 161 isintegral with the depending arm 70 which controls the valve 71 shiftingsaid valve to the left into the position of Fig. 10 to establish fluidconnection between the pump 48 and the right hand end of the cylinder82, thereby actuating the piston 83 to the left to shift the dog bar 23and the reversing dogs carried thereon to the left into the position ofFig. 1, the movement of said dog bar in this direction being limited, asabove stated, by the check nuts 92 on the piston rod.

The operation of the machine which will be and assuming. that anunground workpiece has been placed in the work supporting member 8, themachine is set in operation by movement of a manual reversing lever 162to the left from the position of Fig. v.l, thereby procuring movement ofthe-table 1 to the left to bring the grinding wheel 9 into operativeengagement with the surface of thevworkpiece. During this movement ofthe carriage to the left, an arm 163 carried by the block 42 andnormally hanging in the position shown in Figs. 1 and 9 engages aprojecting portion of the movable member 28 of the switch 29 toreposition said switch in engagement with the stationary contact orswitch portion 30 in readiness for the subsequent energization of themag-' net 32 in response to entry of the roughing gauge within the boreof the workpiece. As the wheel 9 enters the bore of the workpiece, thereversing dog 11 passes over the end of the reversing lever 13 and thecarriage is then reciprocated with the grinding wheel 9 in operativeposition by alternate shifting movement of the reversing lever 13 by thedogs 11 and 12. This reciprocation continues until the roughing gaugeenters the work and establishes an electrical circuit through theelectromagnet 32 elevating the lever arm 40 to procure the extendedmovement of the carriage to the right. During this extended movement,the dressing tools are rocked downwardly into operative position for thedressing operation and the carriage is then reciprocated to return thegrinding wheel 9 into engagement of the work, the dressing tools beingmoved back into inoperative position and the dog "llbeing returned tonormal position. The grinding operation then continues further with thegrinding wheel 9 in operative engagement with the same surface of theworkpiece until the finish gauge enters the workpiece indicating thatthe work is substantially at the desired size. Entry of the finish gaugewithin the workpiece energizes the electromagnet 66, shifting the valve71 to procure movement of the sliding dog bar 23 to the right, andthereby shifting the position of reciprocation of the abrading wheels tobring the polishing wheel 10 into operative engagement with the samesurface of the workpiece.

The crossfeed movement which, prior to this time, has caused a radialfeeding movement of the grinding wheel 9 against the surface of theworkpiece having now been discontinued by the cam 94, the polishingwheel 10 operates, without a cross-feed movement imparted thereto, for apredetermined time subsequent to the entry of the finished gauge withinthe work as determined by the adjustment of the time relay mechanismabove described, the latter being set in operation by entry of theroughing gauge within the bore of the workpiece. After a predeterminedtime interval, the time relay motor 108 energizes the electromagnet 120which procures a radial withdrawal movement of the polishing wheel 10away from the surface of the workpiece and an axial withdrawal movementof the polishing wheel by a run-out of the carriage to rest position. Itwill be obvious that the stock removal by the polishing wheel 10 is sosmall as to be negligible, or in certain cases the small amount of stockremoval by the polishing wheel 10 which brings the workpiece to thedesired size may be provided for by allowing the finish gauge to enterthe bore of the workpiece slightly before the workpiece is at thedesired size.

From the foregoing, it will be apparent that the present inventionprovides for a machine which, while a workpiece is mounted in androtated by a work support, will procure first a grinding operation upona surface of the workpiece and thereafter will procure a polishingoperation on the same surface of the workpiece while said workpiece ismounted in and rotated by the same workholding member. The grindingwheel 9 which performs the grinding operation on the workpiece isarranged -to operate first for a rough grinding on said workpiece andthereafter for a finish grinding, which latter provides a relativelysmooth surface requiring very little polishing by the polishing wheel toprovide a suitable polished surface. Each of the separate abradingwheels is reciprocated over the surface of the workpiece and theposition of reciprocation to maintain either wheel in operative positionis determined by stop members on the reciprocatory carriage of themachine. The position of reciprocation is shifted to withdraw theoperative wheel out of operative position and position the other wheel"in operative position for a cutting operation by the other wheel, thisshifting of the reciprocatory position being procured by shifting saidstop members longitudinally along the carriage. Shifting of the stopmembers is preferably procured by fluid under pressure.

Although in the above specification, the rough grinding and finishingoperations and the polish,- ing operations have been separatelydescribed, it will be noted that the machine once having been set inoperation, it continues through a complete cycle without coming to rest,the complete cycle including both the grinding and the polishingoperations. Thus the abrading operation of the machine when consideredas referring to the automatic cycle of the machine includes both thegrinding and polishing by the. separate wheels.

Iclaim,

i. In apparatus of the class described, a reciprocatory carriage, areversing element to reverse the direction of movement of said carriage,stops on said carriage for engagement with said element to actuate saidelement, and means to shift said stops longitudinally along saidcarriage to shift the position of reciprocation of the carriage 21 Inapparatus of the class described, a reciprocatory carriage, a reversingelement to reverse the direction of movement of said carriage, stops onsaid carriage for engagement with said element to actuate said element,and means actuated in response to the carriage movement to shift saidstops along said carriage to shift the position of reciprocation of thecarriage.

3. In apparatus of the class described, a reciprocatory carriage, areversing element to reverse the direction of movement of said carriage,a pair of stops on said carriage for engagement with said reversingelement, and means to shift said pair of stops as a unit along saidcarriage to shift the position of reciprocation of the carriage.

4. In apparatus of the class described, a reciprocatory carriage, areversing element to reverse the direction of movement of said carriage,a pair of stops on said carriage for engagement with said reversingelement, and means responsive to the carriage movement to shift saidpair of stops as a unit along said carriageto shift the position ofreciprocation of the carriage.

5.. In apparatus of the class described, a reciprocatory carriage, areversing element to reverse the direction of movement of said carriage,a pair of stops on said carriage for engagement with said reversingelement, said pair of stops being movable as a unit along said carriage.

6. In apparatus of the class described, a reciprocatory carriage, areversing element to reverse the direction of movement of said carriage,a pair of stops relatively adjustable toward and away from each other,said stops being arranged to engage and actuate said element, and meansto shift said pair of stops as a unit along said table.

7. In an abrading machine, a work supporting member and a wheelsupporting member, a carriage on which one of said members is mounted, aplurality of abrading wheels carried by said wheel supporting member,means to procure reciprocation of said carriage in one position with oneof said abrading wheels in operative relation to a workpiece in saidwork supporting member, said means including stops on said carriage, andmeans governed by the progress of theabrading operation to. shift saidstops along said carriage to position a second of said abrading wheelsin operative engagement with the workpiece.

8. In an abrading machine, a work supporting member and a wheelsupportingmember, a carriage on which one of said members is mounted, a

plurality of abrading wheels carried by said wheel supporting member,means to procure reciprocation of said carriage in one position withone-of said abrading wheels in operative relation to a workpiece in saidwork supporting member, said means including a pair of stops on saidcarriage, and means governed by the progress of the abrading operationto shift said pair of stops as a unit along said carriage to position asecond of said abrading wheels in operative engagement with the samesurface of the workpiece.

9. m an abrading machine, a work supporting member and a wheelsupporting member, a carriage on which one of said members is mounted, aplurality of abrading wheels carried by said wheel supporting member,means to procure reciprocation of said carriage in one position with oneof said abrading wheels in operative relation to a workpiece in saidwork supporting member, said means including a pair of stops on saidcarriage relatively adjustable toward and away from each other, andmeans to shift said pair of stops as a unit along said carriage toposition a second of said abrading wheels in engagement with the samesurface of the workpiece.

10. In an abrading machine, a work supporting member and a wheelsupporting member, a carriage on which one of said members is mounted,aplurality of abrading wheels carried by said wheel supporting member,means to procure reciprocation of said carriage in one position with oneof said abrading wheels in operative relation to a workpiece in saidwork supporting member, said means including stops *on said carriage,means governed by the progress of the abrading operation to shift saidstops along said carriage to position a second of said abrading wheelsin operative engagement with the workpiece, and'means to return saidstops to original position.

11. In an abrading machine, a work supporting member and a wheelsupporting member, a carriage on which one of said members ismounted, aplurality of abrading wheels carried by said wheelsupporting member,means to procure reciprocation of said carriage in one position with oneof said abrading wheels in operative relation to a workpiece in saidwork supporting member, said means including a pair of stops on saidcarriage, means governed by the progress of the abrading operation toshift said pair of stops as a unit along said carriage to position asecond of said abrading wheels in operative engagement with the samesurface of the workpiece, and means responsive to the carriage movementto return said stops to original position.

12. In an abrading machine, a work supporting member and a wheelsupporting member, a carriage on which one of said members is mounted, aplurality of abrading wheels carried by said wheel supporting member,means to procure reciprocation of said carriage in one position with oneof said abrading wheels in operative relation to a workpiece in saidwork supporting member, said means including a pair of stops on saidcarriage relatively adjustable toward and away from each other, means toshift said pair of dogs as a unit along said carriage to position asecond of said abrading wheels in engagement with the same surface ofthe workpiece, and means responsive to the carriage movement to returnsaid stops to original position.

13. In an abrading machine, a work supporting member and a wheelsupporting member, a carriage upon one of which. said members ismounted, a grinding wheel and a polishing wheel axially spaced on saidwheel supporting member, means to procure reciprocation of the carriageto obtain a longitudinal traverse of the grinding wheel over a surfaceof a workpiece mounted in and rotated by said work supporting member,and means governed by the progress of the grinding operation to shiftthe position of reciprocation of said carriage to position the polishingwheel in operative engagement with the same surface of the workpiece.

14. In an abrading machine, a work supporting member and a wheelsupporting member, a carriage upon one of which said members is mounted,a grinding wheel and a polishing wheel axially spaced on said wheelsupporting member, means to procure reciprocation of the carriage toobtain a longitudinal traverse of the grinding wheel over a surface of aworkpiece mounted in and rotated by said work supporting member,

means governed by the progress of the grinding operation to shift theposition of reciprocation of said carriage to position the polishingwheel in operative engagement with the same surface of the workpiece,and means to procure separation of said wheels from the workpiece at theend of the abrading operation.

15. In an abrading machine, a work supporting member and a wheelsupporting member, a carriage upon one of which said members is mounted,a grinding wheel and a polishing wheel axially spaced on said wheelsupporting member, means to procure a transverse movement between saidmembers, means to procure reciprocation of the carriage to obtain alongitudinal traverse of the grinding wheel over a surface of aworkpiece mounted in and rotated by said work supporting member, meansgoverned by the progress of the grinding operation to shift the positionof reciprocation of said carriage to position the polishing wheel inoperative engagement with the same surface of the workpiece,

16. In apparatus of the class described, a re ciprocatory carriage, areversing element to reverse the direction of movement of said carriage,stops on said carriage for engagement with said element to actuate saidelement, and fluid pressure means to shift said stops longitudinallyalong said carriage to shift the position of reciprocation of thecarriage.

1'7. In apparatus of the class described, a reciprocatory carriage, areversing element to reverse the direction of movement of said carriage.stops on said carriage for engagement with said element to actuate saidelement, and fluid pressure means actuated in response to the carriagemovement to shift said stops along said carriage to shift the positionof reciprocation of the carriage.

18. In apparatus of the class described, a reciprocatory carriage, areversing element to re.- verse the direction of movement of saidcarriage, a pair of stops on said carriage for engagement with saidreversing element, and fluid pressure means to shift said pair of stopsas a unit along said carriage to shift. the position of reciprocation ofthe carriage.

19. In an abrading machine, a work supporting member and a wheelsupporting member, a carriage on which one of said members is mounted, aplurality of abrading wheels carried by said wheel supporting member,means to procure reciprocation ofsaid carriage in one position with oneof said abrading wheels in operative relation to a workpiece in saidwork supporting member, said means including stops on said carriage, andfluid pressure means governed by the progress ofthe abrading operationto shift said stops along said carriage to position a second of saidabrading wheels in operative engagement with the workpiece.

20. Inan abrading machine, a work supporting member and a wheelsupporting member, a carriage on which one of said members is mounted, aplurality of abrading wheels carried by said wheel supporting member,means to procure re-,

ciprocation of said carriage in one position with one of said abradingwheels in operative relation to a workpiece in said work supportingmember,

said means including a pair of stops on said carriage, and fluidpressure means governed by the progress of the abrading operation toshift said pair of stops as a unit along said carriage to position asecond of said abrading wheels in operative engagement with the samesurface of the workpiece.

' 21. In an abrading machine, a work supporting member and a wheelsupporting member, a carriage on which one of said members is mounted, aplurality of abrading wheels carried by said wheel supporting member,means to procure reciprocation of said carriage in one position with oneof said abrading wheels in operative relation to a workpiece in saidwork supporting member, said means including stops on said carriage, agage member adapted to enter the workresponsive to the exte resentspiece when the latter reaches a predetermined size, and means responsiveto the entry of said. gage within the workpiece for shifting said stopsalong said carriage to position a second of said abrading wheels inoperative engagement with the workpiece.

22. in an abrading machine, a work supporting member and a wheelsupporting member, a carriage on which one of said members is mounted, aplurality of abrading wheels carried by said wheel supporting member,means to procure reciprocation of said carriage in one position with oneof said abrading wheels in operative relation to a workpiece in saidwork supporting member, said means including stops on said carriage, agage member adapted to enter the workpiece when the latter reaches apredetermined size, and fluid pressure means responsive to the entry ofsaid gage within the workpiece for shifting said stops along saidcarriage to position a second of said abrading wheels in operativeengagement with the workpiece.

23. In an abrading machine, a work supporting member and a wheelsupporting member, a carriage on which one of said members is mounted, aplurality of abrading wheels carried by said wheel supporting member,means to' procure reciprocation of said carriage in one position withone of said abrading wheels in operative relation to a workpiece in saidwork supporting member, said means including stops on said carriage, agage member adapted to enter the workpiece when the latter reaches apredetermined size, means responsive to the entry of said gage withinthe workpiece for shifting said stops along said carriage to position asecond of said abrading wheels in operative engagement with theworkpiece, and means operative upon shifting of the wheels forretracting the gage from the workpiece.

24. In apparatus of the class described, a reciprocatory carriage, areversing element to re- .verse the direction of movement of saidcarriage, a pair of stops on said carriage for engagement with saidreversing element, means to procure an extended movement of saidcarriage, and means ded movement for shifting the position of said stopsas a unit longitudinally of the carriage. I

25. In an abrading machine, a work supporting member and a wheelsupporting member, a carriage on which one of said members is mounted, aplurality of abrading wheels carried by said wheel supporting member,means to procure reciprocation of said carriage in one position with oneof said abrading wheels in operative relation to a workpiece in saidwork supporting member, said means including stops on said carriage,means for procuring an extended movement of said carriage, and meansresponsive to said extended movement for shifting said stopslongitudinally along said carriage.

DWIGHT C. PAGE.

